4. let zip = customer.address?.postalCode - Here type of postalCode is Int; and that of address is Address? in the Customer struct. What’s the type of zip?

let zip: Customer

let zip: Address?

[CORRECT ANSWER] let zip: Int?

let zip: Int

Hint

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Correct Answer: let zip: Int?

Explanation

The last variable in the chain is postalCode — which of type Int. However, in an optional chain, nil also should be accommodated. If the customer doesn’t have an address (since that is optional), the whole expression will return nil. So, for that reason, the type zip will be Int?.

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